Internet principles of operation

Q1. a)  Describe  Internet. 

❋  The word Internet comes from INTERconnected NETwork.

❋  Internet is the world's largest interconnected network of computer and devices.

❋  Internet Service Provider (ISP) provides Internet to the public to become part of their ISPs network, which is connected to other networks to make up the Internet.

❋  Internet allows to share or exchange information among users through standard internet protocol suite TCP/IP.

❋  Allow users to chat online (via text, audio and video), send and receive emails.

b)  Describe  World Wide Web (www). 

❋  World Wide Web is a collection of websitess, web-pages and other resources stored in web server all over the world.

❋  All web resources of www are accessed using internet.

❋  It allows web-documents to be connected to other document by hypertext links, enabling the user to search for information by moving from one document to another.

❋  HTTP(S) protocols are written using hypertext mark-up language (HTML).

❋  Web-pages and other web resources are identified by Uniform Resource Locators (URL).

❋  A web-browser is used to view web pages that contain text, images, videos, and other multimedia.

c)  Give difference between Internet and World Wide Web.

Internet	World Wide Web (WWW)
It is a worldwide collection of interconnected networks of computers and devices	It uses the Internet to access information from web servers.
It allows the user to send and receive emails.	It is a collection of web pages with multimedia and other information on websites.
Allows online chatting (via text, audio and video)	HTTP(S) protocols are written using hypertext mark-up language (HTML).
Makes use of transmission control protocols (TCP) and internet protocols (IP)	Uniform resource locators (URLs) are used to specify the location of web pages.

Q2. a)  Describe ISP (Internet Service Provider).

✬  Internet Service Provider (ISP) are companies that provide access to the internet to the user.

✬  A monthly fee is usually charged for this service.

✬  The ISP will set up a user account which will contain a username and a Password.

b)  What services are provided by ISP.

1. Internet access.
2. Domain name registration.
3. Web hosting.
4. Online storage service.
5. Email.

Q3. a)  Describe  URL. 

URL stands for "Uniform Resource Locator".
It is the user friendly unique Web address of the web-document or file that you type in the address-bar of your web browser.

URL consists of three parts;

• Protocol.
• Domain name or Website name.
• Webpage or file name.

b)   The web browser breaks up the URL into three components.

Describe the following components of Uniform Resource Locator (URL).

1)   Protocol : 

⇒  The first part of the URL indicates which protocol the browser must use.

⇒  A protocol is a set of rules that must be obeyed when transferring data around a computer network or internet.

⇒  Usually for websites it is the HTTP protocol or its secured version HTTPS.

⇒  HTTP stands for HyperText Transfer Protocol.

⇒  HTTP defines how messages are formatted and transmitted, and how Web servers and browsers should respond to various commands.

2)   Domain name /or/ Website name : 

⇒  Domain name is the user friendly name of a website used in place of technical IP Address of the server hosting a website.

⇒  Its role is to make it easier to access a given website.

3)   Webpage /or/ File Name : 

⇒  File name is the last part of the URL that refers to the file or web page that web browser requests from the web server.

⇒  Web browser either downloads or reads and displays the contents of the file.

c)   Describe the following components of Website name.

1)   Domain host : 

⇒  Domain host is the name of the sub-domain, a part of the main domain or website, where your website files are kept and from where the website can be accessed by your website visitors.

⇒  WWW indicates that the site is part of the web that provides services offered over Internet.

⇒  It allows websites to separate and organize content for a specific function (such as Blog or an Online store) from the rest of the website.

2)   Domain name : 

⇒  Domain name is the name of the website, or root-directory of the website.

⇒  It indicates where we want to go first on the web over internet.

3)   Domain type : 

⇒  Domain type is a domain extension name with 2 or 3 characters separated by period (".") that signifies the type of organization it is associated with, for example, .co, .edu, .com, .org, .net, .gov

⇒  Domain type could include a 2 character domain extension separated by period (".") that identifies the country it is associated with, for example, .uk, .in, .mv, .us

Q4. a)  Describe  Protocol. 

⇒  A protocol is an agreed upon set of rules for exchanging data between two communication devices.

b)  Describe  http  (HyperText Transfer Protocol).

⇒  It is a request-response protocol used for transferring data between a client and server on the internet.

⇒  It is used to load webpages using hypertext links.

⇒  It sends data in plain text format.

⇒  It does not store any information about previous request or responses.

⇒  It sends and receives data over port 80.

c)  Give  difference between  http  and  https. 

⇒  Both HTTP and HTTPS are request-response protocol used for transferring data between client and server on the Internet.

⇒  HTTPS is a secure version of HTTP that ensures the safety of data when transferring files over the internet.

⇒  HTTP sends data in plain text format making it vulnerable to interception and manipulation, whereas HTTPS sends data in encrypted format.

⇒  HTTPS establishes encrypted link between web-server and web-browser using TLS or SSL security protocol.

⇒  HTTP sends data over port 80 while HTTPS uses port 443.

d)  Indicate  how you would know whether or not a website was secure. 

⇒  Secure website uses https protocol in the URL.

⇒  It shows a small padlock in the status bar at the top-left of the address bar of browser screen.

Q5.  Describe  Web Server. 

✬  A dedicated computer that stores, process, and delivers the requested web-pages to the web browser.

✬  The communication between client and server takes place using the Hypertext Transfer Protocol (HTTP) or HTTPS (Secure) protocol.

Q6.  Describe  DNS Server. 

✬  DNS stands for Domain Name System.

✬  DNS server is computer server that stores the database of domain name and its equivalent IP-address.

✬  It translates the domain name to its unique IP-address so that browsers can locate the website and produce the Internet resources to the user.

Q7. a)  Describe  Web browser. 

❋  Web browser is a software used to access information on the World Wide Web.

❋  It is used to locate, retrieve and display the contents of the web-page or web-site.

❋  It interprets, translates and displays the contents of the HTML document.

❋  It interprets, translates and executes the embedded scripts (like javascript).

Example :

b)   State three  functions of a browser. 

⇒  Sends a request to the web server to provide the webpage or web resource.

⇒  Receives data from web server.

⇒  Translates HTML files.

⇒  Processes client-side script, e.g. JavaScript.

⇒  Store / access cookies.

⇒  Stores data in its cache.

⇒  It identifies the protocols such as http, https, ftp etc.

⇒  Downloading file from the web.

c)   Give three  features of a browser. 

❋  Allows to Bookmark the web page which you may need it later (store favourites).

❋  Stores History of the Websites or webpages.

❋  Allows to navigation forward and backward.

❋  Allows to reload or refresh the webpage

❋  Allows multiple tabs / web pages to be opened

❋  Provides Security features.

❋  Find specific text within a web page.

❋  Allows to set a homepage.

Q8.  Explain  how the web browser uses the URL to access the webpage. 

1. The web browser sends URL to DNS server.
2. DNS server stores an index of URL and its matching IP address.
3. DNS searches for URL to obtain the IP address.
4. IP address is sent to web browser, if it is found.
5. Web browser sends request to the IP address of webserver to provide the webpage.
6. Webserver sends web page to web browser.
7. Web browser interprets HTML to display web page.
8. If DNS server-1 cannot find the requested website in its database or cache then its sends out a request to the next DNS server-2.
9. If DNS server-2 finds the URL, then it sends IP-address back to DNS server-1 which puts the IP address and URL into its database and cache.

Q9.  Explain  how  the information stored on a customer's  website is requested and send it to the web-browser to be displayed on the screen. 

⇒  The customer either click on the link or type in the URL or web-address manually in address bar.

⇒  This web address is translates into an IP-address by DNS server.

⇒  Web browser sends a request to the IP-address of web server for the information or resources.

⇒  Web server locates the IP address and sends the HTML code of web page to the browser.

⇒  Browser interprets the HTML code and shows the correctly formatted page on the computer screen.

⇒  Browser sends data to the company’s web-site and is stored in web server.

⇒  Processed data by the company’s web-site is sent back to the browser using customer’s IP address.

⇒  If URL not found DNS returns error.

Q10. a)  Describe  Cookie. 

⇒  Cookie is a text file sent by the web-server to web-browser.

⇒  It is stored in user's computer by web-browser at the request of web-server.

⇒  They are designed to hold data related to a particular client and website.

⇒  It can be accessed either by the web server or the client computer each time when the user visits the web-site.

b)  State three  purpose of Cookies. 

⇒  It stores the website’s Login information.

⇒  It allows the detection of new and repeated visitor of the web site.

⇒  It stores the customization of the web-page. (e.g. like where he left the game or quiz last time / stores items in shopping basket).

⇒  It allows to track user's browsing activities and preferences (like, language, currency and websites they like to visit).

⇒  It help advertisers to show relevant advertisements.

c)  Are Cookie harmful?

No, cookies are not harmful as they are not executable program files. They are simply a text file that stores some data about the user.

Q11.  Cookies are of two types -

1. Session cookies
2. Persistent (permanent) cookies

a)  Explain what is meant by  Session cookies. 

❋  Session cookies exists only in temporary memory and does not store any information on user's computer.

❋  It does not collect any information from the user's computer and does not personally identifies the user.

❋  It stores only user's input and tracks the movements of the user within the website.
For example, when making online purchases, it keeps user's items in a virtual shopping basket.

❋  Session cookies are lost, when the web-browser is closed or website session is terminated.

b)  Explain what is meant by  Persistent (or permanent) cookies. 

❋  Persistent cookies are stored on the hard drive by the web-browser on the request of webserver.

❋  It remains on user's hard drive until the user deletes them or they expire.

❋  It stores the user's login details, settings and preferences that a user has used.

❋  It removes the need to type in login details every time a certain website is visited.

❋  Personal informations are encrypted and stored to prevent unauthorised access.

❋  It helps to create a convenient and faster website experience.

❋  Persistent cookies are a very efficient way of carrying data from one session to another on related websites.

Q12.  Describe three  uses of (persistent) cookies. 

1. Allow the website to remember user's passwords, email addresses and invoice details, so they don't need to type-in the information every time they visit that website.
2. Serve as a memory, enabling the website to recognise users every time they visit it.
3. Save user's items in a virtual shopping basket/cart.
4. Track internet habits and user's website histories or favourities/bookmarks.
5. Store user's preferences to recognise customised webpages.
6. Allow progress in online games and quizzes to be stored.

Q13. a)  A cookie could be used to automatically enter a user’s payment details when the user makes a purchase online.

Describe how cookies can be used to store and  automatically enter a user’s payment details. 

⇒  Cookie is a text file sent by the web-server to the user’s web-browser.

⇒  It is stored in user’s computer by web-browser at the request of web-server.

⇒  User’s payment details are encrypted and stored in this text file.

⇒  When user revisits the website, webserver requests its cookie file to access the data stored in it and automatically enter the payment details.

b)  Explain  why a user may be concerned about their personal data  and online browsing habits  being stored in cookies. 

⇒  User does not know what information is collected and stored in cookies affecting the user’s privacy.

⇒  Computer could be hacked to obtain confidential data stored in cookies.

⇒  Other websites could gain access to the cookies stored on a user’s computer.

⇒  User’s profile could be built and stored in cookie leading to identity theft.

Q14.  HTML can be used to create the structure and the presentation of webpages.

a)  Describe what is  HTML. 

✬  HTML stands for "Hyper Text Markup Language".

✬  HTML is the standard markup language for creating Web pages.

✬  "Hypertext" refers to the text that contains hyperlinks (or links) to other texts and resources.

✬  "Markup language" refers to the way HTML- tags are used to define the Structure and Layout of the web-page.

✬  It is used in processing, defining, and presenting the contents of the web page in web browser.

b)  State the difference between  Structure  and  Presentation  used in HTML webpages.

 Structure : 

⇒  Structure is an essential part of HTML document which includes semantics (HTML tags) and structural markup of the document.

⇒  It instructs how the layout of the content is displayed.

⇒  It stores the overall contents of web-page like Title, Headings, Paragraphs and other resources.

 Presentation : 

⇒  Presentation is the style of the document.

⇒  It instructs how the document will give a pleasing look using different font, colour, style etc.

⇒  The presentation of the web-page is usually kept in separate CSS file.

c)   (i)   Give three example of HTML structure.

1. Giving Title of the web-page, to be shown in title bar of the web-page.
2. Placement of headings and sub-beadings on a web-page.
3. Placement of a paragraph of text on the web-page.
4. Placement of an Image on the web-page.
5. Draw Table to put the contents in rows and columns on the web-page.

(ii)   Give three example of HTML presentation.

1. The colour applied to a text heading, on a web-page.
2. The font style applied to a paragraph of text on a web-page.
3. The font size given to a paragraph of text on the web-page.
4. The size that an image is set to be displayed on the web-page.
5. The height and width of a table is set to be displayed on the web-page.

d)  Explain  why HTML Structure and Presentation files are stored separately.

⇒  Separating presentation file from the structure of the HTML allows a document to be quickly reformated.

⇒  The style of the document could be reused by its name, where ever we need on the web-page.

⇒  The same presentation file could be shared or used by multiple web-pages.

Q15.  Describe "CSS (Cascading Style Sheet)".

⇒  CSS is a style sheet language that describes and stores the styles (like font, size, colour, margins, borders, etc.) used by the HTML elements of a web-page.

⇒  CSS describes how HTML elements should be displayed with pleasing look.

⇒  CSS file is linked to the HTML document to implement the presentation requirements.

⇒  CSS is designed to separate the content of document from its presentation that makes it easier to control the style of the document.